Hish FHRFSRHilffiRteH

WOUGHERMIREGT

Geftain turbocharged oil-burners arle pailicularly suitable forpeilormanee tunirrg.., PeJer Bosenthal repotts.

o a greater or lesserextent, most people arefamiliar with the variousways in which it's

possible to increase the power of apetrol-engined car. lndeed, thereare a myriad of aftermarket tuningfirms to choose from, all dedicatedto the quest of extracting themaximum performance out of the

petrol engine. Which is al lverywell, except for the side-effectsthat extra horsepower usuallycauses; namely far greater fuelconsumption. However, newdevelopments in the tuning ofdiesel engines may change al lthis and chal lenge the dominanceof the petrol engine...

One method of tunino is to 're-

chip' the engine managementsystem; a tuning techniquesuccessfully employed in petrol-engined cars for a number ofyears. There are now chipsavailable for many diesel-enginedvehicles with electronic engine-management systems, and intheory you should be able to getsignificant increases in torque and

power, whilst still retaining the allimportant diesel economy. In thecontext of turbocharged enginesthe improvement in performancecan be particularly dramatic. i

I was fascinated when PeterNoad first broached the subject ofdiesel tuning, in Pacenotes in theNovember'95 issue, and I decidedthat I had to experience a re-

UW Motoring May | 99659

Hish FERFSRHIAH$HO lleftl: UWenthusiast GhrisSmith handled theSuperchipsconuersion.

O (Belowl: TheEPROM chipeinstalled bySuperchips controlthe turbo's boostpressure lll, andthe fuel injectionsystem l2f.

chipped diesel for myself!With four-star petrol typically

costing around t2.50 a gal lon,and with increasing pressure fromthe government to conserve fossilfuels, economical high-performance turbo-diesels couldwell represent the future of sportscars. In the context of a Golf TDl,for example, there already existsa chip giving VR6 levels of torque,with only marginally worseeconomy. Too good to be true?I took my Audi 80 TDl, which hasthe same engine as the Golf TDI,down to Superchips, a specialistin performance chipping, to f indout more.

Superchips were original lyfounded in 1976 by Peter Walesas'Detection Techniques', af irm who special ised in tuningMitsubishi Starion race cars.Peter soon saw the possibilitiesof developing his tuning techniquesto suit road cars, with the first chipproduced being for the Ford RSturbo engine.

Three years ago lan Sandfordtook over as Managing Director,changing the company's name toSuperchips Limited. Their originalcatalogue covered 30 models ofcar; it now covers 50 pages!Re-chipping is big business, andSuperchips are one of the marketleaders, with over 7,800 chips soldin '95. They were also one of thefirst companies to introduce chipssuitable for diesel engines.

Chris Smith, the TechnicalManager at Superchips, is the manresponsible for developing the chipfor the TDl, and he's also a keenVW Audi enthusiast. In the pasthe's oWned a Series 2 Audi 80Sport, and is currently restoring a'71 Type 2 bay window - ready for

the '96 Run to the Sun nodoubt! Chris handled the actualinstal lat ion and set-up of thech ip in my 80 TDl .

The re-chipping processbasically consists of removing thefactory microchips, which controlthe engine's operating parameters,from the engine management's(ECU) printed circuit boards (PCB)and plugging in a re-programmedchip which enables the engine'soperating characteristics to bevaried, and hopeful ly improved!

In the case of the TDI engine,the first step is the removal of thecomplete engine managementsystem, which is hidden behind aplastic tr im panel in the passengerfootwell . The ECU 'black box'canthen be detached as a completeunit, opened up and folded out,revealing two PCBs containing abewildering array ol minuteelectrical components.

The tube running paral lel to thecircuit board originates from theturbocharger and enables the ECUto continual ly monitor and adjustthe boost pressure as required. lfyou look closely at the photographyou can see that this grey boost-tube is attached to a black plasticdevice, the pressure transducer,which converts the analogue boostvariat ions into digital code, whichcan be interpreted by the ECU'smicroprocessor.

There are two microprocessorscontrol l ing the TDI engine'scharacteristics (see the arrowsin the picture); one for the fuel-injection system, and one for theturbo boost levels. The actualchips used are 26-pin EraseableProgrammable Read Only Memory(EPROM) i tems, which can beerased, prior to re-programming,

O TDI engine may look pretty boring, but is much morefun now that it develops an extra 2O bhp!

by removing their label andsubjecting them to ultra-violet l ight.However, in this case the factorychips are not re-programmed;instead Superchips replace bothchips with their own modif iedEPROM units.

The other microchips andcircuitry visible on the PCBscontrol fail-safe systems; a diesel'sECU requires additional safetymeasures compared to a petrolengine's ECU. This is because theflow of diesel must be extremelyaccurate as it directly determinesthe engine speed; i f a petrolengine develops a fault the ECUcan shut off power to the sparkplugs - obviously this isn't anoption for a diesel!

Normally Superchips, or oneof their dealers, would simplysubsti tute modif ied EPROMchips in place of the originalfactory items, check their function,and send the customer on theirway. However, whilst I was at theirfactory they went through thedevelopment sequence for theB0 TDI chip, which was quitefascinating.

Firstly they connect a computerto the car's ECU, run the car ontheir Sun RAM12 rol l ing road and

'read' all the data off the factorychip. This information is fed intotheir main computer'emulator 'programme, which stores all thedata, illustrating it in the form ofa block of numerical code.

The car's boost and injectionchips are then removed altogether,and the car is run directly off theSuperchips emulator computer.Chris wil l then start to alter themapped data fed to the ECU,via the PC screen, and studythe effects on the car'sperformance. All these adjustmentsare made in ' rea l - t ime ' i .e . whi ls tthe car is actual ly running.

The car's performance ismonitored by plotting power andtorque curves, which are obtainedby revving the car up to itsmaximum speed in the f irst fourgears (f i f th isn't used as the higherspeed overheats the rolling-road'sbearingsl). Chris wi l l then increasethe fuel supply at high revs, add alittle more boost pressure, andobserve the effect this has on thepower and torque curves.

This process is repeated untilthe optimum sett ings are found;which aren't necessari ly just themost powerful. l t 's quite fr ighteningto watch your beloved car

UW Motoring May 199660

HWFHmFSRHfifttreHSUPERGHIPS POWER CURUES (Ar THE WHEETSI

roo9(,

80

70

60

50

40

30

20

t o

ofo t5 20 25 30 35 40

MAX POWER 98bhp @ 4200 rpm

repeatedly shrieking its way upto 100 mph, only a few feet awayfrom you! When the fuel supplyand boost pressure were increasedthe wail of the engine took on amuch harder note and began tosound quite meaty! An aggressive-sounding diesel engine seemedlike a contradiction in terms, andwas definitely a new experienceto me!

The original power of the carwas measured as 78 bhp at thewheels, which equates to about92 bhp at the flywheel; prettyhealthy as Audi quote 90 bhp atthe flywheel! The torque wasinitially measured as 134 lbf ft atthe f lywheel, at around 2,100 rpm.It is important to point out thatperformance figures can vary,depending on which rol l ing roadis used, and should not be used toquote exact outputs; they are bestused comparatively,

Initial tests managed to increasethe torque at the flywheel to 169lbf ft, but this was subsequentlyreduced as it meant that theengine produced too much sootyexhaust smoke, and wouldundoubtedly have failed the MoTemissions test. l t was reassuringto see that Superchips took thisresponsible attitude, and weren'tjust interested in extracting themaximum performance irrespective

of cost. After many more rollingroad runs and even moreadjustments, a torque figure of164 lbf ft at the flywheel wasachieved, giving a power outputof 110 bhp at the f lywheel, whichequates to 98 bhp at the wheels( 'at the wheels' f igures are usuallyaround 10 to 12 per cent lowerthan flywheel figures due totransmission losses through thedrivetrain). The exhaust smokewas no more sooty than usualwith this set-up.

At this point, you're probablygetting a bit sick of technical facts,figures and all the other electricaljargon - so was l! | was just itchingto get my hands on the car andgive it some stick! However, Chriswas the first to check it out on theroad, and he returned to ask if itusually had so much torque-steer...

When I drove away fromSuperchips' prernises I didn'timmediately notice any difference,the car st i l l pul led in the same wayfrom low revs, and seemed asflexible as usual. Then I put myfoot down! A gratifying scrabblingnoise from the front tyresaccompanied first gear, and thensecond, shortly followed by abroad grin! The accelerat ion.infirst, and particularly in second,was noticeably fiercer, with theextra torque making for smoolher

progress; less pedal travel nowbeing required to get the car upto speed.

Back at Superchips I asked theobvious question; why don't Audiengineer the ECU l ike this at thefactory? Chris pointed out that re-chipping does increase the strainon the engine sl ightly, although thisis the case with any form of tuning.He also commented, though, thatthe diesel engine is a tough unit,and that several of their test carsare still going strong with over100,000 miles on them. He wenton to point out that manufacturersare constrained by mass-production, and tend to play safewith regard to forthcomingemission standards; thisovercautious approach oftenresults in manufacturers producingcars that are itoo clean'.

All this sounds a bit too good tobe true; can a simple plug-in chip,which only costs around f350,

UW Motorinj May | 9966l

HWFHRFSR HeH

O lAbovef: Long-sufferingfDl endured theSuperchips rolling road...

O (Rightlr ...and the rollingroad at Warwick BanksHandling...

O lBelowf: ...recording amaximum power of 98bhpat the wheels.

performance improvement withoutdramatically increasing the fuelconsumption? There was onlyone way to f ind out.. .

I tested the 'Superchipped'

car for almost 4,000 miles,and carefully monitored the fuelconsumption; this long testdistance kept the inaccuracies to aminimum, and enabled a real ist icaverage mpg figure to be obtained.

In standard form the TDIreturned an average of 47.7 mpgover a 3,794 mile test distance,whilst in Superchipped form 41.2mpg was achieved over a 3,807mile distance.

Over this extended test distanceI have been highly delighted withthe results; the car now pulls likea train al motorway cruisingspeeds, whilst the vaStimprovement in the 50 to 70 mphtime speaks for itself (see theperformance table). The onlynegative point about the chip isthat it has introduced a slightjerkiness at around 1,500 rpm;Superchips reckon that a minoradjustment will eradicate this.

My next port of call was to anindependent diesel tuning specialist,to verify the performance figuresobtained from Superchips, andalso to discover if there were anyadverse side effects to this extrapower.

Warwick Banks Handling, basedat Witham-on-the-Hill, are Land-Rover specialists and experts inthe f ield of dieseltuning. Theykindly offered to help us verify theperformance figures on their rollingroad.

WBH's technical expert, TrevorDavey, commented that he wouldnormally recommend customersto concentrate on intercoolerimprovements as the initial step inseeking extra performance from adiesel engine. He reckoned thatjust fitting an intercooler to apreviously non-intercooled enginewould typically provide around a10 bhp power ga in ; quot ing a 12bhp gain achieved on a Sierradiesel as an example. As such,he was a little sceptical of the chip,viewing it as a somewhat crudemethod of hiking the power output.

To ensure as high an accuracy

as possible on the rolling road, Ihad changed the car's oil the weekbefore, whilst the tyre pressureswere adjusted on the day oftesting. The Clayton rolling roadused had only just been calibratedon the day before, which furtherensured accuracy.

The car was strapped downsecurely and a gauge wasattached to measure boostpressure at the manifold sideof the turbocharger. A large coolingfan helped to keep the enginetemperature reasonable, althoughit still rose to about 20 degreeshigher than usuall The car was runup to maximum speed in fourthgear and then subjected toadditional rolling resistance bypowering down the roller speed.

Quite astonishingly themaximum power output at thewheels was 98 bhp; exactly thesame figure as Superchips hadquoted! The power runs wererepeated several times, with thesame result.

The boost pressure gaugeindicated that the turbocharger wasnow running at a maximum boostpressure o f 1 .1 bar (16 ps i ) ,whereas in standard form itsmaximum operating pressure

had been 0.65 bar (9.4 psi). Thisseemed to be quite a largeincrease in pressure, but Trevorallayed any concern I had; 'that's arelatively low boost pressure, someof the Discoverys we tune operateat a boost of around 1.5 bar (22psi); i t 's certainly not high enoughto affect the reliability'.

All in all, Trevor concluded thatthe chip was providing worthwhileperformance gains, withoutappearing to have any detrimentaleffect to the engine. However, hewasn't so impressed with myaverage fuel consumption of 41.2mpg, and suggested that it shouldbe higher.

However, as the TDI engineoften needs full throttle whenaccelerating, perhaps this higherfuel consumption is a by-productof having an additional 20 bhpunder my right foot. lt certainlycosts a little more to run now,although I definitely think i t 's worthit for the extra power. lf you look atthe performance figures for the B02.0E, i t 's clear that my TDI isquicker and more frugal; a 2.O-l i trepetrol engine will only averagearound 29.5 mpg.

One area of the all-importantrunning costs I haven't touched on

is insurance. Of course, manypeople with re-chipped cars take achance and'forget ' to mention themodification, thus jeopardising anyclaim they may make. Not wantingto take any risks, I contacted myinsurance company (Endsleigh,Tel:01132 448111) and expectedthe worst. I was pleasantlysurprised when they merely askedfor an extra t10 to cover theiradministration costs, and anengineer's report (easily suppliedby Superchips). For those ofyou reading this with a gui l tyconscience, this wi l l hopeful lygive you food for thought!

With al l things considered, theconversion has proved to be avery cost-effective way ofincreasing performance, well worththe 6 mpg loss in fuel consumption.

Superchips have re-chippedaround 1,000 TDI modelsthroughout Europe, and look setto supply many more with thegrowth of their modem-linkeddealers. Who needs a petrolengine? - long l ive the dieseM

Useful GontaetsSuperchips LtdBuckingham Industrial ParkBuck ingham MK181XJTel: (01280) 816781

Warwick Banks HandlingWitham-on-the-HillBourne, LincolnshireTel: (01778) 590500

UW Motoring May 199662

provide a considerable